Air recirculation



Oct. 7, 1958 L. KOZMA AIR RECIRCULATION 3 Sheets-Sheet 1 Filed Dec. 8, 1953 INVENTOR lav/a A azMA BY;

ATTORNE Oct. 7, 1958 1.. KOZMA AIR RECIRCULATION 3 Sheets-Sheet 2 Filed Dec. 8, 1953 WSW 13x 9.6% WQERKQ ON 8 5 ss'szmmaaaa-ss.

INVENTOR [dz/1.: AaZMA ATTORNEY Tlq .7.

Oct. 7, 1958 Filed Dec. 8, 1953 L. KOZMA AIR RECIRCULATION 3 Sheets-Sheet 3 100/: //oZ/m4.

ATTORNEY United States Patent AIR RECIRCULATION Louis Kozma, New Brunswick, N. J., assignor to Johnson & Johnson, a corporation of New Jersey Application December 8, 1953, Serial No. 396,857

2 Claims. (Cl. 1989) This invention is directed to the manufacture of uniform picker laps, that is, picker laps having uniform weight and thickness.

Picking machines, according to known and usual operation of textile mills, are employed to make uniform webs or batts, known as picker laps, which are subsequently to be used as feed material for carding machines. From the standpoint of desired or required performance of carding machines it is important to use as feed material a batt of fibers which has uniformity in weight and thickness, not only in the transverse direction, but also in the longitudinal direction of the picker lap.

Considerable attention has been given in the industry to improving the uniformity of picker laps. The subject is treated, for example, in an article appearing in Textile World, March 1953, beginning at page 118, by Sheehan, How We Make Uniform Picker Laps. These and other articles witness interest in the problem and show ways of offsetting tendency to non-uniformity in picker laps.

A picking machine, according to conventional construction, utilizes a flow of air to deposit suspended textile fibers on the outside surface of foraminous cylinders, which surfaces permit passage of air but collect the fibers. The fiber batt is thereafter removed from the cylinder surfaces as the picker lap.

In respect to longitudinal uniformity of picker laps, attention has been directed to the effect of change of stock, i. e. material fed to the picker, and the importance of properly feeding and blending the stock to the picker. Although, as indicated in the article cited above, attention has been directed to adjustment of machinery and quality control aspects of manufacture of uniform picker laps, the significance of uniformity of air flow and the effect of uniformity of air flow upon uniformity of picker laps has been notably neglected.

One object of the invention is to make more uniform picker laps, as measured in the direction longitudinal and as measured transversely to the lap.

A preferred object of the invention is to effect improved control of picker lap uniformity by a novel feature of air flow control within the picker.

The invention and the manner in which it is carried out, and apparatus features of the invention, may be conveniently understood by reference to the following description taken in connection with the attached drawings in which:

Fig. 1 is an elevation view shown partly in section of a picking machine constructed according to the present invention.

Fig. 2 is an elevation view in greater detail of a portion of the picker machine illustrated in Fig. 1.

Fig. 3 is a view as seen from plane 33 of Fig. 1.

Fig. 4 is a view of the interior of the apparatus, schematic in part, with portions of the housing and machine frame shown in section taken along plane 44 of Fig. 1.

Fig. 5 shows graphs of weight variation traverses across the width of a picker lap made according to the present 2,854,703 Patented Oct. 7, 1958 invention taken at various points along the length of the lap.

Fig. 6 represents graphically variation of the weight of the picker lap of Fig. 5 in the direction of the length of the lap.

Fig. 7 is a graph similar to Fig. 5 based on tests of a picker lap made according to the prior art.

Fig. 8 is a graph similar to Fig. 6 based on tests of a picker lap made according to the prior art.

Reference number 10 designates the housing of a completely enclosed picking machine supported on a substantially air-impervious base 11. Basic elements of the machine include beater 12 mounted on shaft 15 which, in turn, is supported in bearings, not shown, on the machine framework. Beater 12 is provided with three surfaces, preferably cylindrical surfaces 16 supported on arms 17. Active surfaces 16 are provided with a multiplicity of points or teeth 20. Disposed below beater 12 and in close proximity to teeth 20 are a series of adjustable grid bars 21 which form in their entirety a generally cylindrical surface concentric with and in close proximity to the surface of rotation 'of active surfaces 16. Adjacent the last of grid bars 21 there is disposed in an axial direction, and also closely adjacent the cylindrical surface defined by rotation of active surfaces 16, a knife 22 mounted on portion 25 of the machine frame.

Cylindrical screens mounted parallel and with their proximate surfaces adjacent each other .are shown at 30 and 31.

Feed stock 32 is carried on apron 35 supported between rollers 36 and 37 mounted on shafts and bearings not shown. Feed stock 32 is fed to and between driven feed rolls 40 and 41 to active surfaces 16 and teeth 20 thereon of beater 12 rotating in counterclockwise direction, as shown in Fig. 1. Teeth 20 tear segments of fibers from feed stock 32. Teeth 20 co-act with grid bars 21 to effect a degree of fiber separation. Knife 22, coupled with the centrifugal force exerted by beater 12, serve to remove fibers from surfaces 16. The fibers are then thrown toward adjacent surfaces of cylindrical screens 30 and 31. The mats 33 and 34 formed on the screens are drawn by counterclockwise rotation of screen 30 and clockwise rotation of screen 31 into nip 40' between the cylinders.

At the discharge sides of screens 30 and 31 the lap 41 is grasped by draw rolls 45 and 46, and thereafter conveyed as shown on support 49 and between rolls 50, 51 and 52. From roll 52 the lap passes over supporting surface 55 and is wound into roll 56. Roll 56 is formed on floating core 57, and is driven by surface contact with supporting rolls 60 and 61.

The air flow within the picker is of particular significance from the standpoint of the present invention. Consider as a point of initial reference the chamber 62 which is substantially air-tight and formed by the machine frame. Air from zone 62 passes upwardly through the spaces between grid bars 21 and thence in the direction of the suction surfaces 65 and 66 on cylindrical screens'30 and 31, respectively. Suction surface 65 extends circumferetially from nip 40 to leather seal 67 which is secured to the machine frame 10 but is in sliding and substantially air-tight contact with the rotating cylinder 30. In an axial direction suction surface 65 extends the length of the cylinder surface. Each end of the cylinder is sealed to the machine frame in sliding but gas-tight fashion by a cheek block of known construction and design secured to the machine frame and having shape fitting the contour of the cylindrical screen edge.

Suction surface 66 extends from nip 40' to leather seal 70 which is secured to the machine frame as shown and is in sliding but substantially air-tight contact with the rotating surface of cylindrical screen 31. The end edges the same fashion as are the edges of suction surface 65, i. e. by a cheek block not shown which, in fact, may be an extension of the samercheekblockemployed for sealing suction zone 65.

Suction zones65 and .66 are disposed ,onthe inlet which is generally considered tofbe the. rear side. of the picker machine. On the discharge side of the machine, which-is generally considered tube. the front. end, there are disposed additionalsuction zones .71 andr72. Suction zone 71extends from nip 40'; to leather seal. 75 which is secured to the machine. frame and is. in sliding but substantially air-tight contact with the rotating surface of cylinder 30.. Suction surface 72 extends .fromnip 40 to leather seal .76 which :is, also secured to the machine frame and. isqin sliding but gas-tight contactwith the rotating surface of cylinder31. Each of the end. edges of. suction surfaces 71 and 72-is sealed in sliding but gas-tight contact to the machine frame. by suitably shaped cheek blocks not shown butof conventionalconstruction. Each of the cheek blocks has circular edges so designed that the block will fit between the. cylindrical screens into the nip in the area indicated.

Zones and areas of pressure maintained by .a fan, as will be described hereinafter, are indicated in the drawings by dotted areas, whereas the'undotted areas within the confines of the machineare under negative pressure, also maintained by the same fan. The fibers in positive pressure zone 80, which are thrown from beater. 12, are carried by the air stream and by momentum from the beater: toward suction surfaces 65 and 66 and the negative pressure inside cylinders 30 and 31, thereby forming mats 33 and 34 onthe outside surfaces, ofthe cylinders covering suction areas 65 ,and 66.; The webs are maintained by suction against the. cylindrical screen surfaces until ,withdrawn by'draw rolls. 45 and .46, as explained above.

Air from within. cylinder 30 and fromv portions of the machine frame between leather seals 67 and 75 is withdrawn, through opening 81 inthe frame andinto exhaust duct 82. Similarly, suctionismaintained within lower cylinder '31 and portions of the machine frame there- 'below between leather seals. 70 and 76 by exhausting air through opening 85 in the. machine frame and thence into exhaust duct 82. Exhaust duct. 82 leads tothe suction side of fan-.86which. maintainsthepressure relationship described above.

Although suction surfacess65 and 66 ,of cylindrical screens 30 and 31 are designed toremove the maximum amount of. fibers fromair drawn therein, as a practical matter there is always asubstantialamount of fibers, particularly .fine fibers, which. are not filtered out by the screen and which accordingly pass through thescreen into exhaust duct 82 and fan 86. It is. common practice in textile plants of tody to. convey this .air to a central filtering or fiber-removal system, and thereafter exhaust it to the atmosphere.

Itwill now be app'reciatedthat the rate at which fibers are deposited on screens 30 and31 in mats 33 and 34 will be markedly influenced by the rate of air flow from pressure zone 80 to the interior of cylinders 30 and 31. If the pressure differential increases, areas of relatively greaterdensity and weight per unit area will be produced. On the other hand, if the pressure differential decreases a less dense picker lap will result. If pressure differential becomes unduly low, there will be littleor no evening of distributionof the fibers widthwise of the lap normally brought about by the suction; It is seen,.therefore, how variation in pressure differential will produce variation in picker lap weight. and/or thickness in the longitudinal and transverse directions of the lap.

Previously known systems for collecting air from pressure duct 87 conveying air from the discharge side of fan 86 have been characterized by notable, and in many cases, extreme variationin pressure.- One reason for thisvariation is that the fines which are not retained by screens 30 and 31, and which hence pass through connecting conduits into and through'fan 86, tend to clog the duct system downstream from fan 86. For instance, when filters are utilized to remove fines from the air, these filters tend to become clogged, and as they do, they tend to build up pressure thereby retarding flow of air. The pressure built up, as previously indicated, is immediately reflected in non-uniformity of picker laps. Even when filtration of exhaust air is not carried ,out, and a system such as a cyclone separator is employed to remove fines and dust from the exhaust air, variation in load 'on the cyclone separator will cause variation in back pressure which .in turn is reflected innon-uniformity of-picker laps.

According to the present invention the disadvantages of the prior art procedures and machinery are overcome and improvement in picker lap uniformity is realized by recirculating the air exhausted from fan 86 directly, i. e. without filtration, to the picker machine. One embodiment of the invention is illustrated in Figs. 2 and 3 and corresponding parts of Fig. 1. Air from fan 86, instead of being exhausted to filtration or. cyclone separation apparatus through exhaust duct 87, is introduced into battle chamber 90, described in greatest detail in Figs. 2 and 3. Chamber 90 is shown as a substantially rectangular box having a suitable number, i.e. two, bafiles. Battle 91 is shown as extending from the bottom floor 92 of the chamber, and bafiie 95 as extending from the topsurface 96 of the chamber.

in its return passage to the picker. Clean-out door 97 is provided to permit periodic, inspection, clean out and maintenance, if required,

At the front end of chamber 90 there is built in a filter screen 100. The purpose of screen 100 is to bleed out of the recirculating system asmall quantity of air which finds its way into the machine enclosure byreason of slight imperfections in the leather seals, cheek blocks, etc., provided for the purpose of maintaining as nearly as possible air-tight contact between the several surfaces which are moving relative to one another. Although a small amount of air is withdrawn through screen 100, as indicated, the major amount of air leaves battle chamber 90 by way of return duct 101, and is thereby returned to chamber 62 within the picker machine housing.

A notable feature of the inventionis that air is returned directly to the picker without the intervention of, any filtering medium or other element which is likely to cause pressure variation. By reason of this characteristic, pressure differential between zone 80 andthepinterior of cylinders 30 and31, i. e. the pressure dilferential across suction surfaces 65 and 66, is a function only of .theoperation of fan 86. This, of vcourse, can be controlled by design of fan, fan speed, etc., and hence is not susceptible to uncontrolled variation. As indicated above, constant and controlled pressure differential across the suction surfaces makes for. greater uniformity in picker lap weight and thickness, which is a particular object of. the present invention. A further feature of the invention method and apparatus is that fibers which escape retention by screens 30 and 31 are returned directly to the system, thereby effecting an economy in theoperatiorr.

EXAMPLE A standard picker machine of the type illustrated in Fig. l, which was the third unit of a three-process picker, was operated according to the procedure described above to make a uniformpicker lap. Strict middling cotton was used. The bafiied recirculation chamber 90 was employed to assure uniform air flow and uniform static pressures within the picker. The lap produced had a total weight of 50.5 lbs. and a width of about'40 inches: It was analyzed on a. Saco-Lowell' lap .meter to determine the yard-to-yard variation in-..1ap;weight ;bygcutting the approximately 40 in. wide lap, into individual one yard lengths and weighing each yard. The results are plotted By means of the baflles .air passing therethrough is constrained to follow a tortuous course graphically on Fig. 6 wherein the ordinate is ounces per yard length and the abscissa is yards. At the points designated by the letters A through E in Fig. 6 the yard-long cross-width sample referred to above was cut lengthwise of the lap into six equal width segments (each about 6% in. wide), and the segments were weighed. The data for each of the samples A through E are plotted in Fig. 5.

The foregoing picker operation procedure was repeated using the same picker except that bafiled chamber 90 was not used, and instead air from fan 86 was discharged to an air-collecting system. The lap produced, which also had a weight of about 50.5 lbs. and a width of about 40 in., was analyzed for yard-to-yard uniformity on a Saco-Lowell lap meter and for widthwise uniformity according to the procedure described above. Results of widthwise uniformity are plotted in Fig. 7, and results of lengthwise uniformity tests are plotted in Fig. 8. Comparison data for the results obtained with and without air recirculation are presented in Tables 1 and 2.

Table 1 ANALYSIS OF INDIVIDUAL YARD CROSS WIDTH WEIGHT VARIATION Test with Test Percent Cireulawithout Minimum Maximum Average Variation tion Cireula- Wt. Oz. Wt. Oz. Wt. Oz. Based on tion Average A 2. 9 3. 6 3. 3 21 A 2. 6 3. 8 3. 2 37 B 2. 9 3.6 3. 3 21 B 2. 7 3.8 3. 3 33 3.2 3. 4 3. 3 6 O 2. 9 4. 3. 31 D 3. 0 3. 7 3. 4 21 D 2. 7 3. 9 3. 3 36 E 3. 2 3. 4 3. 3 6 E 2. 9 3. 8 3. 4 26 From the standpoint of widthwise uniformity, variation was 33% of average without circulation and 15% of average with circulation.

It will now be apparent that many modifications may be made to the apparatus and method described within the spirit and scope of the present invention. Hence, the scope of the appended claims is not to be limited to the foregoing specific description and illustration.

The claims are:

1. In the manufacture of picker laps in a substantially enclosed picker machine having a fiber-dispersing positive pressure zone, a negative pressure zone and fiber-collecting and lap-forming foraminous suction surfaces between said zones by drawing air and dispersed fibers from said positive pressure zone toward said suction foraminous surfaces, collecting the major portion of said dispersed fibers in a lap of fibers on the pressure side of said suction surfaces and drawing through said suction surfaces the air and a minor portion of said dispersed fibers with a blower located on the downstream side of said surfaces, said air and minor portion of fibers passing into said negative pressure zone, the improvement which comprises recirculating said air and minor portion of fibers by blowing said air and all of said fibers from said blower directly and without substantial decrease in pressure to said positive pressure zone, passing this mixture of air and fibers through a tortuous path including an upward direction, a downward direction, and another upward direction, and bleeding off a minor portion of said recirculated air by filtering through a surface which is substantially parallel to said upward direction.

2. A substantially enclosed picker machine comprising a zone of positive pressure, a rotary element in said zone for dispersing fibers, means for feeding a batt of fibers to said rotary element from outside said machine, a zone of negative pressure in said machine, and separating said zones, a moving foraminous surface for collecting the major portion of said dispersed fibers while permitting passage of air through said foramens and into said negative pressure zone, a fan for maintaining said positive and negative pressures, an unobstructed conduit providing a free flow of air connecting the discharge side of said fan to said positive pressure zone for recycling air from said negative pressure zone directly to said positive pressure zone, said conduit including a chamber containing baffle means providing an upward path, a downward path and another upward path, and air filtering means adjacent to and having a surface substantially parallel to the latter path.

References Cited in the file of this patent UNITED STATES PATENTS 1,761,493 Rogers June 3, 1930 1,767,957 Bachman June 24, 1930 2,086,517 Aldrich July 13, 1937 2,206,297 Curley et al July 2, 1940 2.431,066 Miller Nov. 18, 1947 FOREIGN PATENTS 688,216 Germany Feb. 15, 1940 

